1. Field of the Invention
The invention relates to a pressure compensator device adapted to be fitted to a proportional type hydraulic distributor provided with a passage for sensing the load pressure, and a hydraulic distributor incorporating the pressure compensator device.
2. Description of the Prior Art
A proportional type hydraulic distributor of this kind is described in French Pat. No. 2,562,632. The hydraulic distributor includes a distributor slide valve sliding in a bore in a stator that is actuated by at least one control pressure so that the slide valve, which has progressive action notches, moves across openings provided in the bore of the stator, being fed through a compensator slide valve, and, inside the stator, a pressure sensing passage which communicates at all times with the compensator slide valve spring chamber so as to superimpose on the action of this spring, on the compensator slide valve, the action of the pressure in this passage. The pressure sensing passage further communicates with at least one distributor chamber of the stator which the distributor slide valve causes to communicate alternately with the return circuit when the slide valve is in a neutral rest position or with a load circuit when the distributor slide valve feeds this circuit.
The usual commercial name for information sensing of this kind is "load sensing." The objective of a system of this kind is to transmit to a device adjusting the pressure of the installation the highest pressure required by the most heavily loaded equipment. This makes it possible to adjust the pressure of the circuit to the precise value needed to feed the various equipment loads that it controls.
To this end the hydraulic distributor of the aforementioned patent features a fluid flow rate to the main slide valve that is regulated by a compensator or balancing slide valve, the position of which depends on the value of the load pressure in the sensing passage. Inside the balancing slide valve is a check valve to prevent any possibility of reverse movement of a receiver. Reverse movement of this kind would tend to arise if a receiver were subjected to a fore against which a displacement is to be made, especially if the pump feeding the circuit has not yet reached the pressure needed to overcome this force.
Generally speaking, it is found that this structure is fully satisfactory for operation at moderate feed rates. However, when the flow rate reaches high values the head losses across the compensator slide valve become very high and they affect the efficiency of the distributor.
An object of the present invention is to avoid these disadvantages by proposing a new arrangement for the compensator slide valve.